Fluid operated percussion drill or hydraulic hammer



y 1967 H. L. FOSTER 3,322,207

FLUID OPERATED PRECUSSION DRILL OR HYDRA Filed Nov. 12, 1964 5 Sheets-Sheet 1 ULI C HAMMER fluer/ .4. F0; fer

IN VENTOR.

BY 5 j ATTORNEY May 30, 1967 FLUID OPERATED PRECUSSION DRILL OR HYDRAULIC HAMMER Filed NOV. 12, 1964 H. 1.. FOSTER 3,322,207

5 Sheets-Sheet 2 Wade/z 1. F05 fer INVENTOR.

A TTOF/Vf) y 1967 H. L. FOSTER 3,322,207

FLUID OPERATED PRECUSSION DRILL OR HYDRAULIC HAMMER Filed Nov. 12, 1964 3 Sheets-Sheet. 3,

..--/5Z i /54 K 2 x I -/5 I I U6 f/z/e/r Z. FOJ/e/ INVENTOR BY ME? ATTORNEY -embodiment of the hammering tion, showing details of construction of the same, and of United States Patent Ofilice 3,3222% Patented May 30, 1967 3,322,207 FLUID OPERATED PERCUSSION DRILL R HYDRAULIC HAMMER Hubert L. Foster, Houston, Tern, assignor to Foster- Gardner Tool Company, Houston, 'Iex., a partnership Filed Nov. 12, 1964, Ser. No. 410,430 8 Claims. (Cl. 173-43) This invention relates to hammering mechanism for use in the drilling of wells, and more particularly to hammering mechanism for incorporation in a rotary drilling string and which is operated by the circulation of fluid through the string.

In the drilling of wells, such as gas and oil wells, it is customary to make use of a tubular drilling string, to which a rotary bit is attached at the lower end to be rotated in contact with the formation at the bottom of the well bore. Drilling mud, or other suitable liquid is circulated downwardly through the string and upwardly in the bore through the annulus surrounding the string to lubri cate the bit and carry away cuttings formed during the drilling operation.

The rate of penetration of the formation in drilling operations by this method is, in part, dependent upon the weight applied to the bit through the string, and it has been found that a substantial increase in the rate of penetration may be obtained by delivering a downward impact to the bit during rotation of the same. It has also been found desirable under some circumstances, such as under conditions in which the string may become stuck in the well bore, to deliver an upward impact to the string, or to produce both an upward and a downward impact to the string or cause the same to vibrate during the drilling operation.

The present invention has for an important object the provision of hammering or impact delivering mechanism for incorporation in a drilling string used in the carrying out of drilling operations of the kind mentioned above, and which is operated by the flow of fluid through the string.

Another object of the invention is to provide hammering mechanism of the type referred to which operates in response to the flow of fluid through the string but which is free from the effects of water hammer or hydraulic hammering which often occurs due to the positive interruption of fluid flow in a system of this character.

A further object of the invention is the provision of hammering mechanism adapted to be incorporated in a drilling string for operation by the flow of fluid through the string and which is constructed to permit the continuous, uninterrupted flow of fluid during the operation of the mechanism.

Another object of the invention is to provide hammering mechanism of the kind mentioned which is easily assembled and connected into a drilling string and in which the parts are easily replaceable for purposes of maintenance or repair.

The above and other important objects and advantages of the invention will be apparent from the following detailed description, constituting a specification of the same when considered in conjunction with the annexed drawings, wherein:

FIGURE 1 is a fragmentary, vertical, central, crosssectional view, on a reduced scale, of a well bore, showing the lower portion of a drilling string therein with the hammering mechanism of the invention incorporated therein and the drilling bit attached to the lower end of the string;

FIGURES 2A, 2B, 2C and 2D are fragmentary, vertical, central cross-section views, illustrating a preferred mechanism of the invenwhich FIGURE 2B is a downward continuation of FIG- URE 2A, FIGURE 2C being a downward continuation of FIGURE Z-B and FIGURE 2D being a downward continuation of FIGURE 2C;

FIGURE 3 is a cross-sectional View, taken along the line 3-3 of FIGURE 2 B, looking in the direction indicated by the arrows; and

FIGURE 4 is a cross-sectional view, taken along the line 4-4 of FIGURE 2B, looking in the direction of the arrows.

Referring now to the drawings in greater detail, the invention is illustrated herein in connection with its use in a drilling string of conventional type having sections of drill pipe or drill collars, such as indicated at 10, in FIG- URE l, threadably connected together and to the lower end of which a drilling bit 12 of usual construction is attached to be rotated with the string in a well bore W in the drilling of the well. The hammering mechanism of the invention, generally designated 14, is incorporated in the drilling string by connecting the same to the lower end of the section 10 and to the upper end of the drilling bit 12, as by means of an upper end sub 16 and lower coupling elements 18 and 20.

The hammering mechanism of the invention has an outer tubular barrel or case which may be formed in a number of threadably connected sections, such as those indicated at 22, 24 and 26, the uppermost of these sections being connected to the lower end of the upper sub 16 and the lower end of the lowermost section 26 being connected to the upper end of the coupling element 18.

Within the outer barrel an inner tubular hammer member is movably disposed for longitudinal, reciprocating movement, which member is conveniently made up of the upper, intermediate and lower sections 28, 30 and 32, respectively, which are threadably secured together as shown at 34 and 36. The upper end 37 of the uppermost hammer section 28 is formed with an externally enlarged portion 38, which is slidably positioned within a generally sleeve-like, upper anvil member 40 positioned in an internal enlargement 42 in the upper barrel section 22, wherein the anvil member is held by engagement at its lower end with an internal shoulder 44 in the barrel and at its upper end with the lower end 4-6 of the upper sub 16. The external enlargement 38 is provided with an external annular groove 48 for the reception of suitable packing, such as an O-ring 50 to form a fluid tight seal between the hammer and the internal surface of the anvil member 40.

The lower end section 32 of the hammer is engageable at its lower end with the upper end 52 of the coupling element 20, which forms the lower anvil of the mechanism, as best shown in FIGURE 2C.

The lower end portion of the lower hammer section 32 is slidably fitted into the lower barrel section 26, which is provided with an internal annular groove 54 for the reception of suitable packing, such as: the O-ring 56 to form a fluid tight seal between the hammer and barrel at the lower end of the hammer. An annular space 25 is provided surrounding the hammer, between the same and the internal surrounding surface of the barrel or case.

Within the tubular hammer a generally sleeve-like inner tubular liner is positioned which is made up of an upper liner section 58, an intermediate liner section 60, and a lower liner section 62. The upper liner section 58 is seated at its upper end against an internal annular shoulder 64 in the upper hammer section 28, as seen in FIGURE 2A, and at its lower end on the upper end of the intermediate liner section 60, as seen in FIGURE 2B, while the lower end of the intermediate liner section abuts against the upper end of the lower liner section 62, as shown at 63 in FIGURE 23, and the lower liner section 62 is seated D at its lower end on an internal annular upwardly facing shoulder 66 in the lower hammer section 32, as seen in FIGURE 2C. The inner liner made up of the sections 58, 6t] and 62 is thus held in the hammer between the upper shoulder 64, seen in FIGURE 2A and the lower shoulder 66 seen in FIGURE 2C.

Within the inner liner a tubular valve seat forming member is disposed in the intermediate liner section 60, which member is formed of upper and lower parts 68 and 741, respectively, as shown in FIGURE 2B, the upper part 68 being in engagement at its upper end with an internal annular, downwardly facing shoulder in the intermediate liner section 69 and at its lower end with the upper end of the part 70, while the part 70 is in engagement at its lower end with the upper end of a sleeve 72 which in turn is seated on a valve seat element 74 in the lower end of the liner section 60 and which extends into the upper end of the lower liner section 62, for engagement at its lower end with an internal annular, upwardly facing shoulder 76.

The upper part 68 has at its upper end a valve seat 73 and the lower part 70 has at its lower end a similar valve seat 80.

An internal annular, upwardly facing shoulder 82 is formed within the upper end of the intermediate liner section 60, upon which a valve seat element 84 is seated at its lower end, which element is also seated at its upper end against an internal annular, downwardly facing shoulder 86 in the lower end of the upper liner section 58.

Within the intermediate liner section 60', a main valve structure, generally designed 87, best shown in FIGURE 2B, is slidably positioned for longitudinal movement into and out of closing relation to the valve seats 78 and 30. This main valve structure is formed of upper and lower parts 88 and 90, the lower end of the upper part 88 having an externally threaded, reduced portion 92 which is threaded into an internally threaded upper end bore 94 in the lower part 90. A washer 96 is held between the upper and lower parts to form an external annular projection against which the upper end of a coil spring 28 bears, whose lower end is seated on an internal annular shoulder 100 in the part 70, whereby the main valve yieldingly urged to a longitudinally centralized position within the parts 6% and 70 of the valve seat forming member.

The main valve is formed at its opposite ends with externally enlarged portions 102 and 164 respectively, the portion 102 having oppositely facing annular valve seating faces 106 and 108, while the portion 1114 has similar faces 1111 and 112. The main valve portion 102 has an end bore 114, from which passageways 116 open outwardly through the seating face 108, and the portion 104 is similarly provided with an end bore 118 from which passageways 120 open outwardly through the seating face 112.

When the main valve is in its uppermost position, as shown in FIGURE 2B, the seating face 106 will be in closing contact with the lower end seat of the member 84, the passageways 116 being then open, while the seating face 112 -will be in closing relation to the lower end seat 80 of the part 7 to close the passageways 120, the seating face 110 being then out of closing relation to the seat forming member 74. In the downmost position of the main valve, the lower passageways 120 will be open and the lower seat forming member 74 will be closed, while the upper passageways 116 will be closed and the upper seat forming member 84 will be open.

An upper pilot valve carrying an adjusting rod 124 is threadably attached at its upper end to the upper anvil member 411 for longitudinal adjustment relative thereto, as seen at 126 in FIGURE 2A, the rod being provided with a lock nut, or the like, for maintaining the rod at any selected position of longitudinal adjustment.

The rod 124 has a plunger 128 fitted thereon, near its lower end, which plunger is provided with suitable seal forming means, such as that indicated at 130 to form a seal between the rod and the internal surface of the upper liner section 58. A nut 132 is threaded on the lower end of the rod 124, which nut has an elongated portion 134 formed with a lower end enlargement providing an external annular shoulder 136. An upper auxiliary, or pilot valve 133, of generally tubular configuration, closed at its lower end, surrounds the elongated portion 134 of the nut 132 for longitudinal movement in the upper liner section 58, which valve has an internal, upper end shoulder against which the upper end of a coil spring bears, whose lower end is seated on the shoulder 136 to yieldingly urge the valve upwardly on the rod 124. The rod 124 also has a reduced lower end portion 142 providing an external shoulder 144 against which the upper end of a coil spring 14-6 bears, whose lower end is seated against the inside of the lower end of the valve 13% to yieldingly urge the valve downwardly relative to the rod 124. The pilot valve 133 is thus mounted on the rod 124 for longitudinal movement relative thereto.

The lower end of the valve 138 is shaped to seat against the upper seat forming member 84 to close the member upon upward movement of the inner tubular hammer.

A lower pilot valve carrying rod is attached at its lower end to the lower anvil member 20, as by means of an externally threaded, tubular fitting 152, which is threadably connected to the anvil member in surrounding relation to the lower end portion of the rod and engages a lower end enlargement 154 formed thereon. The rod 150 has a lower end bore 156 which is in communication with the central, fiuid passageway 15% of the bit 12, and is provided with side ports, such as those indicated at 160 which open outwardly from the bore 156 to the exterior of the rod. This rod 150 is provided near its upper end with a plunger 162 similar to the plunger 128 of the upper rod 124 and having suitable packing, such as that shown at 164 similar to the packing 131) to form a seal between the lower rod and the surrounding internal surface of the lower liner section 62. A lower pilot valve 166 which is of similar construction to the upper pilot valve 138 is similarly mounted on the upper end of the lower rod, for longitudinal movement relative thereto and to function in the same manner. The lower pilot valve 156 is shaped for engagement with the lower valve seat forming member 74 to close the same upon downward movement of the hammer and to be subsequently moved to open position by engagement with the lower end of the main valve when the main valve moves downwardly.

The sub 16 which connects the upper end of the outer barrel to the lower end of a section 170 of the drilling string above, as seen in FIGURE 2A is formed with a downwardly opening cavity 172 in its lower end for the reception of the upper end of the upper rod 124 which cavity is in communication with the interior of the drilling string and with passageways, such as those indicated at 174 in the upper anvil member 40, which open into the interior of the barrel, exteriorly of the hammer. As will be apparent from the drawings, the hammer is spaced inwardly from the surrounding internal surface of the bar-rel from the sub 16 to the lower section 32 of the hammer, and this lower section 32 has passageways 176 leading from the interior of the barrel externally of the hammer to the interior of the hammer from whence fluid may flow through the side ports 160 of the lower rod 150 into the bore 158 of the bits 12. Thus fluid may flow from the drilling string above the hammer, through the barrel exteriorly of the hammer and into the bore 156 of the lower rod 15 through ports 160 whereby drilling fluid will be supplied to the bit 12. The passageways 176 may be of predetermined size, or may be provided with chokes, such as that indicated at 175, to restrict the flow of fluid therethrough, as desired.

The inner liner, made up of the sections 58, 60 and 62 is spaced inwardly from the surrounding wall of the harm mer to form an annular passageway, designated 180 in FIGURES 2A, 2B and 2C, which passageway is in communication at its lower end with the interior of the hammer through passageways 182, shown in FIGURE 2C, and at its upper end through passageways 184, shown in FIGURE 2A.

The intermediate section 60 of the inner liner is formed with external, peripherally spaced, bosses 186 and 183, adjacent its upper and lower ends, which engage the surrounding wall of the hammer to hold the liner in inwardly spaced relation to the hammer and through which upper ports or passageways 190 and lower ports or passageways 192 lead from the exterior of the hammer to the interior of the liner, as seen in FIGURE 2B. The intermediate section of the liner also has an external boss 194 through which a passageway 196 leads from the exterior of the hammer to the interior of the parts 68 and 70 of the inner valve seat forming member. Additionally the intermediate section of the liner is provided with ports 198 leading from the exterior of the liner to the interior thereof at locations to be in communication with the upper passageways 116 of the main valve when the main valve is in its upmost position, and with the lower ports 200 through which fluid may flow from the exterior of the liner through low passageways 120 of the main valve when the main valve is in its lowermost position.

The hammering mechanism of the invention is shown in the drawings with the hammer thereof in its lowermost position in the barrel, the lower end of the hammer being in contact with the lower anvil face 52, and the main valve being in its uppermost position in the hammer. In this condition of the mechanism fluid will be flowing downwardly in the barrel about the exterior of the ham mer, through passageways 176 int-o the interior of the hammer and through ports 160 of the lower rod 150 into the bore 158 of the bit 12. The interior of the hammer exteriorly of the inner liner will also be filled with the fluid which may flow through the passageways 182 from the lower section 32 of the hammer into the annular space within the hammer surrounding the inner liner. The fluid may also flow into the interior of the liner through the upper passageways 198 which are now open through the upper main valve passageways 116, to allow the fluid to flow into the liner above the main valve through the upper end bore 114 and valve seat member 84.

During upward movement of the hammer, the main valve will be in the upmost position shown in FIGURE 2B, and the fluid in the chamber or power cylinder 59 of the hammer may flow out through bore 114 and passageway 198, while at the same time fluid will flow into the lower chamber or power cylinder 63 through passageway 192 to hold the valve in its up position and to exert a lifting force on the hammer.

Just before the hammer actually strikes the upper anvil, the upper pilot valve 138 will close the bore 114, so that the outflow of fluid from chamber 59 is shut off, and the pressure in chamber 59 increases until it becomes sufficient to overcome the total upward pressure being exerted on the lower end of the main valve to move the main valve downwardly.

As the main valve moves away from the seat element 84 fluid may flow therethrough through the passageway 190, the pilot valve 138 being still seated on the main valve to close the bore 114.

Pressure from the exterior of the hammer may then enter the chamber 59 through passageway 190, so that downward pressure isnow exerted on the upper end of the main valve and on the upper pilot valve, to move the main valve to its lowermost position, closing passageway 192 and opening passageway 200 to allow exhaust through passageways 120 and 200 while the inflow through passageway 192 is shut off. At this time the hammer will have started its downward movement.

In this condition of the mechanism, the fluid pressure is applied to the upper end of the main valve through passageway 190 to hold the valve in its downmost position until the hammer has moved downwardly far enough to 6 engage the lower pilot valve 166 with the lower end of the main valve to close the bore 118, whereupon the operation is again reversed to cause the hammer to return upwardly.

It will be apparent that the flow of fluid through the mechanism continues without interruption, whether or not the hammer is in operation, so that there is no hydraulic or water hammer effect during the operation of the mechanism. Moreover, it will be evident that the upper rod 124 may be adjusted longitudinally to position the pilot valves relative to the hammer at locations to product either an upward hammering or a downward hammering or both upward and downward hammering as may be desired.

The hydraulic hammer is in a case or barrel, with high pressure fluid in the annular space 25, completely surrounding the hammer. The pressure fluid enters the upper end sub 16, flows around the upper anvil member 40 and proceeds to the ports 192 of the main control valve.

In the operation of the equipment the main slide valve 87 will initially be in the up position with the hammer resting on the lower anvil 20. As the pressure enters the pressure ports 192, shown in FIGURE 2B, the complete hammer moves upwardly to the end of the up stroke until it hits the upper pilot valve 138, shown in FIGURE 2B. This reverses the action of the hammer, and the hydraulic pressure drive the hammer downwardly at full force until it hits the anvil 20, an instant after the main valve hits the lower pilot valve 166 the movement of the main slide valve 87 is reversed and the hammer again moves upwardly.

The exhaust pressure of the spent hydraulic fluid becomes equalized inside of the hammer at each end thereof in the hammer cylinders 41, 21, and equally balances the hammer from opposite ends, by the static pressure of the fluid. The buoyancy of the hammer will thus be the same regardless of the depth or pressure. This also maintains the valve 87 in a condition such that high pressure is applied to one side of the valve while exhaust is applied to the other side of the valve, and the only area, subject to high pressure, to move the hammer is within the valve itself, which ever direction it may be going.

The pressure in the annulus 25 will also be exerted equally over the entire external surface of the hammer. If the volume of fluid flow is more than the drill needs, small chokes 178, in the lower hammer end 32, shown in FIGURE 2C, allow the excess fluid to flow out into the exhaust stream, all of the fluid eventually passing downwardly to the end of the drill and into the bit. This keeps the fluid that might have grit or grime in it clean, in the hammer cylinder. The internal surface of the casing about the hammer is constantly washed by the fluid flowing through the annulus 25 and any sand or grit therein is carried away through the chokes 178 out into the exhaust stream, which prevents the hammer from sticking due to accumulation of sediments therein. The upper hammer cylinder within the upper anvil member 40 is also similarly washed, there being always a higher pressure at one side of the ring groove 48 than on the other side thereof.

The upper end of the rod 124 is shaped as shown in FIGURE 2A, for the application thereto of a wrench by which the rod may be turned to adjust the length of the hammer stroke by shortening or lengthening the rod. By loosening lock nut 126 and adjusting rod 124 the stroke may be made shorter or longer" as desired. The hammer may be made to hammer both upwardly and downwardly by increasing the effective length of the rod 24 to lengthen the stroke of the hammer. The mechanism may thus be adjusted to hammer either upwardly or downwardly alone, or both upwardly and down-wardly when desirable. The stroke of the hammer may also be adjusted at the bottom end as by means of the insertion of a spacer or washer, not shown, between the lower end of the rod and the coupling element 20, seen in FIGURE 2D. The hammer may thus be prevented from hitting the bottom end anvil 2t and will only strike the upper anvil on the upstroke.

In extracting or fishing, as the case might be, such adjustment is very important since it makes possible the use of the equipment for this purpose without the necessity of changing the drill, it being only necessary to adjust the stroke of the hammer.

The reciprocating motion of the hammer is controlled by the center main slide valve 87, and each end pilot valve 138 and 166. Each end pilot valve is spring loaded, so that it may move in either direction. The spring action is for the purpose of positioning the pilot valve at the proper place between strokes of the hammer. The springs 140, 146 and 168, 170 do not perform any other work except to move the pilot valves to neutral position.

The main slide valve 37 is floating, so to speak, in the center of two different power cylinders 59 and 63, in one of which there is a high pressure, and the other of which there is a low pressure. At the high pressure end of the valve pressure will be exerted through the exhaust outlet ports 120 for example, against exhaust seat St This keeps the valve 87 from being too hard to move at the end of its dwell in that position and lets the pilot valve 166 have energy enough, under the influence of the hydraulic pressure to move the valve in the opposite position. There are no springs to do anything other than to keep the valve 87 from falling or settling down at the end of its stroke.

The main slide valve 87 is actually a double-ended four-way valve. It has pressure ports 190, 192 at each end that are completely opened when the valve 87 is in the position of opening the pressure ports 190, 192, and completely closing the exhaust ports 116, 1.20, for each power cylinder. This structure makes it possible for the valve 87 to run at high speed. Moreover, the pressure fluid may exert a force on the ports 68 and 7t) internally thereof through the passageway 196, as shown in FIGURE 2B, to adjust the distance between the seats 78 and 80 in case the valve 78 should become heated and change in length to automatically adjust the valve 78 to the correct length.

The operating fluid driving this drill or hammer has several useful functions: one, to reciprocate the engine; two, to have power fluid on one side of the main slide valve 87 on an equal area of the main slide valve 87 as the area thereof which is exposed to the exhaust pressure. Also, the fluid pressure is used to reciprocate the entire hammer. The entire volume of the fluid goes through the hammer or drill into the bit as in the conventional drilling equipment to keep the bit clean and return to the surface with the cuttings or dirt. The fluid keeps a continuous balance of pressure on the inside of the hammer regardless of which direction it may be flowing exteriorly of the hammer in the annular pace 25. The reciprocating motion of the hammer is controlled by the pressure of the fluid flowing downwardly through the string. To slow the hammer to a minimum it is only necessary to slow down the operation of the equipment that supplies the fluid or provide a bypass valve for the fluid, as the case may be. This provides an arrangement which may be accelerated at will just as in other types of engines. Such a mode of operation is very useful in carrying out drilling operations, since it is not necessary to run at maximum rpm. under conditions in which half speed is sufficient for the purpose. There is a slight fluctuation in the gauge pressure at the end of each stroke which may serve to indicate the speed of the hammer. Moreover, the frequency of vibration may also be measured to determine the speed of the hammer.

The pressure of the fluid operating the mechanism is at no time completely interrupted or stopped, so that there is no water hammer effect. The reason for this is the area of the valve mechanism involved in shifting the stroke from one direction to the other is the same area which is involved in moving the hammer up or down. Thus, the volume of fluid is continually used to do work rather than being alternately stopped and started. The elimination of any water hammer effect provides the advantage that injury to the equipment is thereby avoided.

It will be apparent that in removing the string from a well the fluid may drain out of the string.

At the bottom of tool shown in FIGURE 4, the control rod which carries the piston 162 and pilot valve 166, is securely fastened to the anvil 20 against which the harnmer strikes, making it possible to provide a space for free motion for the bit or anvil to move, independent of the drill pipe or tubing which is connected to the tool. This causes the impact to be delivered to the formation which is being drilled rather than on the piping. By this arrangement the string need not follow the hammer up and down in time with the movements of the hammer. The pilot valve is thus fastened to the anvil through a rod which in turn reciprocates with the anvil, but which also has a predetermined length which may be adjusted to change the length of the stroke, to provide upward and downward impact, or both.

At the upper end of the drill as shown in FIGURE 1, the upper adjustment means in anchored to the outer case or collar. This adjustment means is stationary insofar as the reciprocating motion of the hammer is involved. Thus, the load of the pipe or the weight of the drill pipe can be controlled from above without affecting the length of the stroke of the hammer. This adjustment is through the rod 124 which is securely anchored to the outer case of the drill or hammer. By adjusting the rod 124 upwardly to its full length the pilot valve 138 will be timed so that the hammer will hit at the upper end of the stroke. By adjusting the length of the rod the length of the stroke may be adjusted as desired. In order to cause the hammer to hit a harder blow the pressure of the fluid flowing downwardly may be increased.

On the up-stroke, as the main valve reaches the upper pilot valve, the pressures are shifted, so that the main valve is moved down upon contact with the upper pilot valve, the high pressure keeping the main valve seated in the down position so the tool or hammer will hydraulically move to its lower position. Upon downward movement the main valve contacts the lower pilot valve which is automatically shifted and the back pressure holds the main valve in its shifted position in the hammer until the main valve again contacts the upper pilot valve.

It will be apparent that the removal and replacement of the internal mechanism of the invention is easily accomplished.

It will thus be seen that the invention constructed and operated as described above provides fluid flow actuated hammer means which is efficient in operation, having few moving parts, and which is capable of easy adjustment and replacement.

The invention is disclosed herein in connection with a particular embodiment of the same, but it will be understood that this is intended by way of illustration only and that various changes can be made in the construction and arrangement of the parts, within the spirit of the invention and the scope of the appended claims.

Having thus clearly shown and described the invention, what is claimed as new and desired to secure by Letters Patent, is:

1. In a pressure fluid operated hammer for use in the drilling of wells, a tubular casing, means for connecting the easing into a string of drill pipe for rotation with the string in a well bore and through which fluid may flow through the casing, means forming an upper and a lower anvil in the casing, a tubular hammer movably disposed in the casing for longitudinal movement into and out of engagement with the anvils, means on the casing extending into and slidably engagable with the hammer in position to form therewith a chamber in the hammer whose opposite ends are closed, upper and lower ports in the hammer through which fluid may flow into and out of said chamber, means in said hammer positioned for coaction with said ports to prevent the inflow of fluid to and allow the outflow of fluid from said chamber through said upper ports and to prevent the outflow of fluid from and allow the inflow of fluid to said chamber through said lower ports upon downward movement of the hammer to cause the hammer to move upwardly and to prevent inflow of fluid to and allow outflow of fluid from the chamber through said lower ports and prevent outflow of fluid from and allow inflow of fluid to said chamber upon upward movement of the hammer to cause the hammer to move downwardly.

2. In a pressure fluid operated hammer for use in the drilling of wells, a tubular casing, means for connecting the casing into a string of drill pipe for rotation with the string in a well bore and through which fluid may flow through the casing, means forming an upper and a lower anvil in the casing, a tubular hammer movably disposed in the casing for longitudinal movement into and out of engagement with the anvils, an upper and lower rod attached at their outer ends to the casing and whose inner ends are extended into the hammer, sealing means between the rods and hammer located to form a closed chamber in the hammer, upper and lower ports in the hammer through which fluid may flow into and out of said chamber, valve means in the hammer including valve members on said rods and seal forming means positioned for coaction with said members and ports to prevent the inflow of fluid to and allow the outflow of fluid from said chamber through said upper ports and to prevent outflow of fluid from and allow inflow of fluid to said chamber through said lower ports upon downward movement of said hammer to cause the hammer to move upwardly, and to prevent inflow of fluid to and allow outflow of fluid from said chamber through said lower ports and to prevent inflow of fluid to and allow outflow of fluid from the chamber through said upper ports upon upward movement of the hammer to cause the hammer to move downwardly,

3. In a reciprocating, fluid flow operated hammer a tubular casing adapted to be connected into a flow line, means in the casing forming longitudinally spaced anvils therein, a tubular hammer movably disposed in the casing for longitudinal movement into and out of engagement with said anvils, an inlet and an outlet port at each of two longitudinally spaced locations in the hammer, valve means movably disposed in the hammer for longitudinal movement therein and closing the hammeragainst the flow of fluid therethrough between said locations, and means responsive to the continuous flow of hydraulic fluid between said locations for moving the valve means to a position to close the inlet port and open the outlet port at one of said locations and to close the outlet port and open the inlet port at the other of said locations upon movement of the hammer in one direction and to another position to close the inlet port and open the outlet port at said other location and open the inlet port and close the outlet port at said one location upon movement of the hammer in the other direction.

4. In a reciprocating, fluid flow operated hammer a tubular easing adapted to be connected into a flow line, means in the casing forming longitudinally spaced anvils therein, a tubular hammer movably disposed in the casing for longitudinal movement into and out of engagement with said anvils, an inlet and an outlet port at each of two longitudinally spaced locations in the hammer, valve means movably disposed in the hammer for longitudinal movement therein and closing the hammer against the flow of fluid therethrough between said locations, means responsive solely to the continuous flow of hydraulic fluid between said locations for moving the valve means to one position to close the inlet port and open the outlet port at one of said locations and to open the inlet port and close the outlet port at the other of said locations upon movement of the hammer in one direction and to another position to close the inlet port and open the outlet port at said other location and open the inlet port and 10 close the outlet port at said one location upon movement of the hammer in the other direction, and means for regulating the movement of said valve means to vary the length of the stroke of said hammer.

5. In a reciprocating, fluid flow operated hammer a tubular casing adapted to be connected into a flow line, means in the casing forming longitudinally spaced anvils therein, a tubular hammer movably disposed in the casing for longitudinal movement into and out of engagement with said anvils, an inlet and an outlet port at each of two longitudinally spaced locations in the hammer, and means for causing reciprocating movement of the hammer in response to continuous flow of hydraulic fluid into and out of the hammer through said ports comprising, a main valve movably disposed in the hammer for longitudinal movement therein and closing the hammer against the flow of fluid therethrough between said locations, a pilot valve for each end of said main valve, means for supporting the pilot valves for coaction with said main valve upon movement of the hammer in either direction, said main valve and said pilot valves being positioned for coaction to close the inlet port and open the outlet port at one of said locations and to close the outlet port and open the inlet port at the other location upon movement of the hammer in either direction.

6. In a reciprocating, fluid flow operated hammer a tubular casing adapted to be connected into a flow line, means in the casing forming longitudinally spaced anvils therein, a tubular hammer movably disposed in the casing for longitudinal movement into and out of engagement with said anvils, an inlet and an outlet port at each of two longitudinally spaced locations in the hammer, and means for causing reciprocating movement of said hammer in response to a continuous flow of hydraulic fluid into and out of said hammer at said locations comprising, a main valve movably disposed in the hammer for longitudinal movement therein and closing the hammer against the flow of fluid therethrough between said locations, a pilot valve for each end of said main valve, means for supporting the pilot valves for coaction with said main valve upon movement of the hammer in either direction, said main valve and said pilot valves being positioned for coaction to close the inlet port and open the outlet port at one of said locations and to close the outlet port and open the inlet port at the other location upon movement of the hammer in either direction and means for adjusting the positions of said pilot valve longitudinally relative to said main valve to regulate the length of the stroke of said hammer.

7. In a reciprocating, fluid flow operated hammer a tubular casing adapted to be connected into a flow line, means in the casing forming longitudinally spaced anvils therein, a tubular hammer movably disposed in the casing for longitudinal movement into and out of engagement with said anvils, an inlet and an outlet port at each of two longitudinally spaced locations in the hammer, and means for causing reciprocating movement of the hammer in response to a continuous flow of hydraulic fluid into and out of the hammer at said locations comprising, a main valve movably disposed in the hammer for longitudinal movement therein and closing the hammer against the flow of fluid therethrough between said locations, a pilot valve for each end of said main valve, means for supporting the pilot valves for coaction with said main valve upon movement of the hammer in either direction, said main valve and said pilot valves being positioned for coaction to close the inlet valve and open the outlet valve at one of said locations and to close the outlet valve and open the inlet valve at the other location upon movement of the hammer in either direction and means for adjusting the positions of said pilot valves longitudinally relative to said main valve to cause the hammer to engage one of said anvils upon movement of the hammer in one direction and to reverse the movement of the hammer prior to en- 1 1 gagement of the hammer with the other of said anvils upon movement of the hammer in the other direction.

8. In a reciprocating, fluid flow operated hammer a tubular casing adapted to be connected into a flow line, means in the casing forming longitudinally spaced anvils therein, a tubular hammer movably disposed in the casing for longitudinal movement into and out of engagement with said anvils, an inlet and an outlet port at each of two longitudinally spaced locations in the hammer, and means for causing reciprocating movement of the hammer in response to continuous flow of fluid into and out of the hammer at said locations comprising, a main valve movably disposed in the hammer for longitudinal movement therein and closing the hammer against the flow of fluid therethrough between said locations, a pilot valve for each end of said main valve, means for supporting the pilot valves for coaction With said main valve upon movement of the hammer in either direction, said main valve and said pilot valves being positioned for coaction to close 12; the inlet port and open the outlet port at one of said locations and to close the outlet port and open the inlet port at the other location upon movement of the hammer in either direction and before the hammer reaches the limit of its movement in either direction.

References Cited UNITED STATES PATENTS 2,132,962 10/1938 Mueller 173-115 2,748,712 6/1956 Sargent 91-229 2,758,817 8/1956 Bassinger 173-73 2,774,334 12/1956 Cline 173-73 3,010,439 11/1961 Mee et a1. 91-229 3,101,796 8/1963 Stall 173-73 FRED C. MATTERN, JR., Primary Examiner. L. P. KESSLER, Assistant Examiner. 

1. IN A PRESSURE FLUID OPERATED HAMMER FOR USE IN THE DRILLING OF WELLS, A TUBULAR CASING, MEANS FOR CONNECTING THE CASING INTO A STRING OF DRILL PIPE FOR ROTATION WITH THE STRING IN A WELL BORE AND THROUGH WHICH FLUID MAY FLOW THROUGH THE CASING, MEANS FORMING AN UPPER AND A LOWER ANVIL IN THE CASING, A TUBULAR HAMMER MOVABLY DISPOSED IN THE CASING FOR LONGITUDINAL MOVEMENT INTO AND OUT OF ENGAGEMENT WITH THE ANVILS, MEANS ON THE CASING EXTENDING INTO AND SLIDABLY ENGAGABLE WITH THE HAMMER IN POSITION TO FORM THEREWITH A CHAMBER IN THE HAMMER WHOSE OPPOSITE ENDS ARE CLOSED, UPPER AND LOWER PORTS IN THE HAMMER THROUGH WHICH FLUID MAY FLOW INTO AND OUT OF SAID CHAMBER, MEANS IN SAID HAMMER POSITIONED FOR COACTION WITH SAID PORTS TO PREVENT THE INFLOW OF FLUID TO AND ALLOW THE OUTFLOW OF FLUID FROM SAID CHAMBER THROUGH SAID UPPER PORTS AN TO PREVENT THE OUTFLOW OF FLUID FROM AND ALLOW THE INFLOW OF FLUID TO SAID CHAMBER THROUGH SAID LOWER PORTS UPON DOWNWARD MOVEMENT OF THE HAMMER TO CAUSE THE HAMMER TO MOVE UPWARDLY AND TO PREVENT INFLOW OF FLUID TO AND ALLOW OUTFLOW OF FLUID FROM THE CHAMBER THROUGH SAID LOWER PORTS AND PREVENT OUTFLOW OF FLUID FROM AND ALLOW INFLOW OF FLUID TO SAID CHAMBER UPON UPWARD MOVEMENT OF THE HAMMER TO CAUSE THE HAMMER TO MOVE DOWNWARDLY. 